Mobile communication systems were developed to provide mobile users with communication services. With the rapid advance of technologies, the mobile communication systems have evolved to the level capable of providing high speed data communication service beyond the early voice-oriented services.
Recently, the next generation mobile communication system moves its focus to Human to Machine (H2M) and Machine to Machine (M2M) communication beyond Human to Human (H2H) communication. In order to meet such a requirement, the 3Rd Generation Partnership Project (3GPP) communication standard organization is standardizing on Machine Type Communications (MTC). MTC has characteristics different from those of the conventional radio communication. The MTC characteristics are classified variously depending on the usage purpose. For example, the MTC devices requiring communication a few times a day without periodicity have delay tolerant characteristic. In contrast, the MTC device fixed at a location to collect and transfer predetermined information has the characteristic of low mobility. The mobile network operator has to provide services in consideration of the coexistence of the MTC devices having various characteristics and legacy terminals.
Typically, a plurality of MTC devices exists within a cell. If the MTC devices attempt access simultaneously, the load of the access network may increase abruptly. This makes the network unstable and, as a consequence, most of the terminals are likely to fail initial access. Since the most MTC devices have delay tolerant characteristic, it is not necessary to establish connection to the base station immediately. If the load of the radio network exceeds a predetermined threshold value, the base station may restrict the initial attach of the MTC devices first to control the radio network load. The 3GPP working groups are discussing adoption of an extended access baring technique to control the radio access network lode. The normal access barring technique information is carried in a System Information Block (SIB).
The present invention proposes an access barring technique capable of controlling aforementioned various service accesses, particularly emergency call and MTC accesses.